The present invention relates generally to connectors and, more specifically, to a connector for use with optical fibers or electrical conductors and having a latch to effect its disengagement with a mating connector.
Optical fiber connectors are an essential part of substantially any optical fiber communication system. For instance, such connectors are used to join segments of fiber into longer lengths, to connect fiber to active devices such as radiation sources, detectors and repeaters, and to connect fiber to passive devices such as switches and attenuators. The principal function of an optical fiber connector is to hold two optical fiber ends such that the core of one of the fibers is axially aligned with the core of the other fiber. This way, all of the light from one fiber is coupled to the other fiber. This is a particularly challenging task because the light-carrying region (core) of an optical fiber is quite small, for example, in single-mode optical fibers the core diameter is about 8 microns.
Because of the growing acceptance of optical fiber in television, data, and telephone (multimedia) communications, the need to provide higher density interconnection arrangements has emerged. Furthermore, it is always desirable to reduce cost while still providing a connector that is acceptable to customers. Recognizing the engineering challenge posed by the alignment of two very small optical fiber cores, it is still desirable to provide connectors which are smaller, less expensive, and yet more convenient for users to manipulate.
To this end, a connector was introduced which is described in detail in U.S. Pat. No. 5,481,634, which is hereby incorporated by reference in its entirety. This connector is commercially available from Lucent Technologies as the Lucent LC connector, and is referred to herein as the xe2x80x9cLC connector.xe2x80x9d Reference is made to FIG. 9 which shows a perspective view of an optical fiber connector 110 which, together with bend-limiting strain-relief boot 102, terminates optical cable 130. This optical fiber connector has a generally rectangular shape with a square cross section. The outside surface of the connector 110 includes a spring latch 120 which is used for securing the connector to an associated receptacle in order to prevent unintended decoupling between the two.
Spring latch 120 is molded into the housing and includes a xe2x80x9cliving hingexe2x80x9d 125 which allows tab 126 to be moved up and down in a direction which is generally perpendicular to the central axis of connector 110. Spring latch 120 includes a pair of shoulders 121 that are positioned on opposite sides of a tab 126 and are automatically deflected downward during insertion into an associated receptacle. Spring latch 120 returns to its original position by its own restorative force. Each of the shoulders 121 includes a vertical surface 122 which interacts with a corresponding vertical surface within the receptacle to hold the connector 110 and receptacle together, that is, until the latch is once again deflected downward and the connector is partially ejected from the receptacle due to the force from an internally disposed spring used to bias the ferrule forward. It is noted that latch 120 is a cantilever beam which is made from a material that can be deformed somewhat by the application of force, but returns to its original shape after the force is removed. The connector and latch are typically molded from a commodity thermoplastic in order to achieve a low-cost, lightweight housing for optical components contained therein. A fingernail groove 123 is positioned at the back end of latch 120 along with a tab head 124 that facilitates manipulation of latch 120. Although the LC connector is effective in providing alignment of two very small optical fiber cores, it tends to have an awkward feel when being released from a mating connector. More specifically, when releasing the latch, there is a tendency to push the connector forward thereby making the backward withdraw of the connector from the receptacle more difficult. This is especially true if the LC connector is in a confined space and there is little room to manipulate the latch. Such a situation arises, for example, when the LC connector is integrated with a built-out attenuator (BOA).
The applicant has recognized that the principal cause of the connector""s awkward feel and its tendency to be pushed forward when being released is the combination of the inaccessibility of the preferred location to depress the latch--namely the area around the fingernail groove 123, and the geometry of the accessible portion--namely the tab head 124, which has a backward slope. When a user attempts to depress the latch and is unable to reach the area around the fingernail groove 123 as is often the case when the connector is used in a tightly-packed backplane application or is coupled to a BOA, he is more or less forced to apply force to the more-accessible but backward-sloping tab head 124. Any downward force applied to the tab-head will necessarily have a forward force component associated with it due to the slope of the tab head. Thus, the action of the user depressing the latch by using the tab head 124 will cause the connector to be pushed forward thereby making release from the associated connector more difficult.
The awkward feel of the LC connector is magnified with the anti-snag protector embodiment as shown in FIG. 10. This embodiment is described in detail in U.S. Pat. No. 5,719,977. Briefly, the latch 120 comprises a trigger 130 which prevents the connector 110 from snagging on other cables. The patent also states that the trigger 130 makes the latch 120 easier to operate. When releasing this latch 120 with the trigger 130, however, not only must the user overcome the problems described above with respect to the latch 120, but also he must overcome a forward force vector imparted by the trigger 130 itself. More specifically, the trigger 130 pivots about a single rear point. Since the trigger is attached to the housing of the connector at a single point, the trigger necessarily travels in an arc when being actuated to effect the connector""s release. This arc necessarily means that a component of the force being applied to the trigger, at some point, is not perpendicular to the axis of the housing. In other wards, during a portion of the trigger""s travel during actuation, a component of the force used to actuate the latch is axial to the housing. Furthermore, given the forward rotation and particular geometry of the trigger 130, this axial force component is directed forward, particularly during the beginning of its deflection. Therefore, as the user actuates the latch, a forward axial force is applied to the connector making its withdrawal from the receptacle more difficult.
Therefore, a need exists for a connector which is similar in size and function to the LC-connector but which does not introduce a forward force component when its latch is actuated. The present invention fulfills this need among others.
The present invention is directed to a connector having a latching mechanism, which, when actuated, does not introduce a significant forward force to the connector. To this end, the latching mechanism comprises an articulated latch having joints configured such that the moment on one side of the actuation point is substantially reduced if not canceled by an opposing moment on the opposite side of the actuation point. This way, the net rotation on the latch is minimized. Minimizing the net rotation on the latch reduces the axial force on the connector.
In a preferred embodiment, the connector comprises: (a) a housing having a longitudinal axis and a front and back orientation and being adapted for receiving a signal carrying medium; and (b) an articulated latch connected to the housing at one or more primary joints and having a plurality of sections, wherein at least one of the sections has an engagement structure which is adapted to engage a corresponding structure on the mating connector such that the connector and the mating connector cannot be separated without actuating the latch, and wherein at least two sections are connected at a secondary joint, the primary and secondary joints being configured such that, when an actuating force is applied to the articulated latch, a moment on one side of the actuation point is reduced by an opposing moment on the opposite side of the actuation point, reducing the axial force on the connector.